Field of the Invention
The present invention relates to gas demand devices.
Related Art
Gas demand devices are used to provide controlled amounts of gas for inhalation by persons. Two examples of these kinds of devices include oxygen demand devices for patient oxygen therapy and oxygen demand devices for airplane crew and/or passengers in low oxygen or low pressure environments aboard aircraft.
Oxygen demand devices in the home healthcare market have for many years improved the usable duration of supply vessels (cylinders, tanks, containers, etc.) over continuous flow devices (regulators, flowmeters, liquid oxygen dewars, etc.) while still adequately satisfying the clinical needs of the oxygen patent. These systems typically only provide oxygen to the user during the inhalation portion of a breath, optimally in the first half of the user's inhalation.
Initially most devices were electronic using batteries as a power source. Later, pneumatic device using the pressure in the supply vessel as a power source became the preferred systems due to no need for batteries, smaller size and ease of use. Both types afforded the oxygen patient to ambulate for longer periods of time and/or require less frequent oxygen supply refills.
Weight reduction in aerospace is a constant goal to reduce fuel consumption, increase range and improve safety. Current systems for on-board oxygen provide continuous flow oxygen which limits supply duration, requires the maximum size supply vessel storage space will allow regardless if used which in most flights they are not and can limit aircraft range.
Some home healthcare demand systems have been tried in commercial aviation market with limited acceptance and success. Most were not durable enough for the rigors of the commercial aviation market or provide inadequate interface with the aircraft storage system.
Therefore it is an object of the invention to provide a method and apparatus for regulating gas flow that does not experience the exhibited by conventional gas flow regulation methods and apparatuses.